Every organization, from Apple and Google to the US government, demands different skills and personal qualities in its leadership.

But research suggests there are two traits that are common to the majority of successful leaders: extroversion and conscientiousness.

According to a meta-analysis led by Timothy Judge, Ph.D., a professor at the Mendoza College of Business at the University of Notre Dame, extroversion is the best predictor of leadership effectiveness (typically measured by assessments from subordinates and supervisors), followed closely by conscientiousness.

Psychologists define extroversion as sociability and enthusiasm, while conscientiousness refers to your organization and work ethic. More recent research has found that conscientiousness is the only major personality trait that consistently predicts success, largely because highly conscientious individuals are good at setting and working toward goals.

The meta-analysis also offers some clues to why extroversion is so closely related to leadership. When Judge and his co-authors deconstructed the big personality traits, they found that dominance and sociability better predicted leadership than extroversion as a whole (though they caution that few studies looked at both these components of extroversion at the same time).